In their most basic form, hair fixative compositions contain a film-forming resin, typically a polymer, which acts as the hair fixative in the composition. The resin can be applied to the hair in the form of a spray, either via a spray pump or an aerosol spray, or in the form of a gel.
In aerosol hair spray systems, the resin usually is dissolved in an organic solvent, such as ethanol or isopropyl alcohol, and delivered via a propellant, which is usually a volatile hydrocarbon. These systems are becoming less desirable due to the consumers' perception that alcohol in hair sprays can dry and damage hair, and due to environmental regulations limiting the emission of volatile organic compounds (VOC) into the atmosphere. As used herein, a volatile organic compound is an organic compound containing at least one, but not more than 10, carbon atoms, except for those organic compounds having a vapor pressure of less than 0.1 mm Hg at 20.degree. C. There is an on-going effort by the hair care industry to replace the VOC with water. However, the inclusion of significant amounts of water in hair fixative compositions has created problems relating to solubility and dispersability of the hair fixative resin in the compositions, to application of the hair fixatives to the hair and to performance of the hair fixative once applied to the hair.
There is a need in the industry for low VOC, aqueous-based, hair fixative compositions and hair fixative polymers which are dispersable or soluble in water, which can be applied readily to the hair, and which provide acceptable hair fixative properties, such as strength, i.e., holding power or stiffness, humidity resistance, film clarity, aesthetics and removability from hair using conventional shampoo and/or water.
One such approach to lower VOC hair fixatives is disclosed in U.S. Pat. No. 5,021,238, in the name of Martino et al. Two-phase, aqueous-based, hair-fixing aerosol systems which utilize dimethyl ether as a propellant are disclosed. The system can be shaken to form a semi-stable emulsion or mixture which is stable for a time sufficient for spraying.
Another approach to significantly reducing or totally eliminating VOC in hair fixatives is the use of water-dispersable or water-soluble polymers in an aqueous-based hair fixative gel. Such gels which are available currently utilize poly(vinyl pyrrolidone) (PVP) or derivatives thereof, such as poly(vinyl pyrrolidone/vinyl acetate) copolymers (PVPNA), as the hair fixative resin contained therein. PVP has relatively low glass transition temperature, i.e., about 80.degree. C., and is very sensitive to water or humidity. It is desirable, then, to find a water-soluble polymer to replace PVP. The polymer should be less sensitive to water, form clear films upon drying, and provide the hair fixative gels with hair fixative properties which are as good as or better than hair fixative gels which contain PVP as the fixative resin.